Italian Patent Application No. 3376 A/87 and corresponding U.S. application Ser. No. 07/154,782 filed concurrently herewith, an automatic machine is known for the continuous production of dual-use filter sachets for infusion products with succesive bags or pouches containing fractional doses of said products.
This machine has along the production line, a succession of means including means for progressively fold back and seal longitudinally a strip of thermally weldable filter paper in a flattened tubular form oriented horizontally and to thermally weld the tube transversely so as to enclose the individual fractional doses between two successive transverse thermal welds.
Rotary wheel means has pickup elements for applying to said flattened tube equidistantly spaced labels, a longitudinally continuous thread transversely contacting said labels as well as thermally weldable stickers or tabs through alternate transverse thermal welds partly to the backs of the.
As means is provided for cutting up the tube thus mode into portions comprising of at least two bags and for setting up these bags against each other and sealing together their extremities.
A dual-use filter sachet with multiple bags or pouches in succession or in series, each containing a corresponding fractional dose or unit quantity of the infusion product allows for the two modes of use, one in the flattened form to be collated in lots for the sale of said bags or pouches in superimposed or back-to-back arrangement by folding one bag or pouch over or adjacent to the other, and one mode in an unfolded or extended arrangement of said bags or pouches. The thread has a length which is substantially equal to the length of the sachet in its unfolded use arrangement of the bags or pouches, and is fixed to the opposing extremity of said sachet by means of a sticker or tab made of a thermally weldable material together with the label made of a nonweldable paper in the proximity of said opposing extremity so that the thread can longitudinally surround the outside of the sachet when these bags or pouches are in their back-to-back collated arrangement in lots for sale.